Which of the following statements is/are true.

A) ${\mathrm{Na}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ is more soluble in water than ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$.

B) ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ is used as a primary standard in volumetric analysis.

C) Both ${\mathrm{Na}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ and ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ are strong oxidizing agents.

D) The chromates and dichromates are inter-convertible in aqueous solutions.

The statements are given.

A) Compared to ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ , ${\mathrm{Na}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ is more water soluble(because solubility of dichromates of alkali metals decreases on going down the group)
B) The primary standard in volumetric analysis is ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ .
C) ${\mathrm{Na}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ and ${\mathrm{K}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7$ are both potent oxidizing agents.

D) In aqueous solutions, depending on the pH of the solutions, chromates and dichromates can be converted into one another.